The role of lysosomal enzymes in the initiation and propagation of the inflammatory response has been demonstrated to occur by two major mechanisms: 1) interaction with circulating humoral factors such as complement components, and 2) direct release of cationic proteins and enzymes capable of degrading connective tissue. In addition, it has been postulated that a third mechanism might be operative, namely the local synthesis of low molecular weight substances such as prostaglandins. The proposed research study would determine the applicability of these mechanisms to the generation and propagation of periodontal inflammation as well as investigate the effects of released granule enzymes on viable cells. This study will: 1) involve the separation of lysosomes from the various types of circulating blood cells and a determination of their capacity to interact with and generate phlogistic mediators from complement components; 2) determine if the postulated synthesis of biologically active prostaglandins by lysosomal phospholipase A acting on cell membrane in the presence of the requisite cytoplasmic enzymes is a mechanism by which inflammation might occur; 3) determine the effect of granule lysates on viable cells; and 4) study the role of the above mechanisms in the production of inflammation in the patient with periodontitis. In the latter, it is proposed that the results obtained in patients prone to severe periodontal disease and its concomitant complications be compared to a similar group of patients having periodontal inflammation, but lacking complications.